The Philippine Coast Guard (PCG) set up five navigational buoys, each one 30-feet long and bearing the national flag, near Lawak (Nanshan), Likas (West York), Parola (Northeast Cay), and Pag-asa (Thitu) islands from May 12 to 14, Adm. Artemio Abu, the service’s commandant, told a local radio station, reports Radio Free Asia (RFA).

Abu hailed “the resounding success of installing our sovereign markers.”

On May 17, he said, the coast guard also established new command observation posts on Lawak, Likas, and Parola to boost Manila’s “maritime domain awareness” in the South China Sea, which Filipinos refer to as the West Philippine Sea, and is crisscrossed heavily by international vessels.

An estimated USD 5 trillion in international trade transits through the waterway yearly.

Several Vietnamese and Chinese fishing boats, as well as China Coast Guard vessels, he noted, had been spotted in the vicinity of Pag-asa Island, the largest Philippine-held territory that houses a Filipino civilian community.

“The ships from Vietnam and China showed respect for the mission we undertook,” Abu said, adding that the Philippine Coast Guard boats were prepared to challenge the foreign vessels in case they interfered with the mission to install the navigational buoys and command posts.

Sourced from Spain, the buoys are equipped with “modern marine aids to navigation” including lanterns, specialized mooring systems, and a satellite-based remote monitoring system able to transmit data to coast guard headquarters in Manila, Abu told RFA.